It's rubbed on the skin to reduce signs of aging and consumed by athletes to improve endurance, but scientists now have the first evidence of one of vitamin E's normal body functions. The powerful antioxidant found in most foods helps repair tears in the plasma membranes that protect cells from outside forces and screen what enters and exits, Georgia Health Sciences University (GHSU) researchers reported on December 20, 2011 in the journal Nature Communications. Everyday activities such as eating and exercise can tear the plasma membrane and the new research shows that vitamin E is essential to repair. Without repair of muscle cells, for example, muscles eventually waste away and die in a process similar to what occurs in muscular dystrophy. Muscle weakness is also a common complaint in diabetes, another condition associated with inadequate plasma membrane repair. "Without any special effort we consume vitamin E every day and we don't even know what it does in our bodies," said Dr. Paul McNeil, GHSU cell biologist and the study's corresponding author. He now feels confident about at least one of its jobs. Century-old animal studies linked vitamin E deficiency to muscle problems, but how that happens remained a mystery until now, Dr. McNeil said. His understanding that a lack of membrane repair caused muscle wasting and death prompted Dr. McNeil to look at vitamin E. Vitamin E appears to aid repair in several ways. As an antioxidant, it helps eliminate destructive byproducts from the body's use of oxygen that impede repair. Because it's lipid-soluble, vitamin E can actually insert itself into the membrane to prevent free radicals from attacking. It also can help keep phospholipids, a major membrane component, compliant so they can better repair after a tear.